The Internet of vehicles has become a hot field for development of wireless communication technologies, wherein Vehicle-to-Everything (V2X) communication (including Vehicle-to-Vehicle (V2V) communication, Vehicle to Infrastructure (V2I) communication and Vehicle-to-Pedestrian (V2P) communication) is a technology with the greatest impact on a wireless transmission technology in the field of the Internet of vehicles, and V2V communication is a core of the V2X communication technology. V2V may share sensing information of an on-board radar, a camera and the like (i.e. sensor sharing) between vehicles through wireless communication between the vehicles to extend sensing ranges of the vehicles from a sight distance range of tens of meters to a non-sight distance range of hundreds of meters, thereby greatly improving driving safety of the vehicles and effectively implementing aided driving and automatic driving.
However, a V2V communication system is a complicated wireless communication system confronted with many technical challenges, and one of the technical challenges is that: it is required that it supports hundreds of vehicles to simultaneously send sensor sharing information within a range of hundreds of meters, and meanwhile, it is required that a low delay and high data transmission reliability is maintained. Therefore, usage of a V2V resource scheduling technology capable of effectively suppressing interference between terminals is required.
An existing V2V technology, i.e. Institute of Electrical and Electronic Engineers (IEEE) 802.11p, may merely adopt a pure Ad-Hoc networking and scheduling manner for lack of cooperation of a cellular network. However, such a scheduling manner is relatively lower in efficiency, and along with increase of a number of terminals, a V2V communication delay may gradually be increased, and a transmission success rate may gradually be reduced.
A Long Term Evolution (LTE)-based V2X technology under research and standardization of the 3rd-Generation Partnership Project (3GPP) is expected to achieve V2V transmission performance higher than the IEEE 802.11p, this is because it may perform centralized scheduling on V2V terminals by virtue of a base station of an LTE cellular network to greatly improve V2V transmission efficiency, reduce a V2V transmission delay and increase a transmission success rate.
Such a scheduling technology combining base station centralized scheduling and Ad Hoc scheduling has been adopted in an LTE Device-to-Device (D2DD) standard, and thus an existing LTE V2X technical solution mainly references the LTE D2DD design. An LTE V2V system is formed by an LTE network and On Board Units (OBUs). FIG. 1 is a deployment scenario of an existing V2V system.
In a scenario in coverage of an LTE base station (called as an In Coverage scenario), the base station firstly assigns Sidelink resources to an OBU terminal for V2V transmission, and then the OBU terminal uses the resources assigned by the base station to transmit Sidelink data and transmission parameters thereof.
If the coverage of the LTE base station is unstable, there are no signals sometimes (called as a Partial coverage scenario) and the base station cannot dynamically assign the Sidelink resources to the terminal in real time, the base station periodically broadcasts information of a semi-static resource pool, and as long as the OBU terminal receives the information of the resource pool when being in coverage, Sidelink resources may be randomly selected from the resource pool to send V2V data and transmission parameters thereof when the terminal is out of coverage.
In a scenario completely out of the coverage of the LTE base station (called as an Out of Coverage scenario), it is even impossible for the OBU terminal to occasionally receive the information of the resource pool in a broadcast message of the base station. Under such a condition, Sidelink resources may only be randomly selected from a preconfigured resource pool statically stored in the terminal to send the V2V data and the transmission parameters thereof.
However, randomly selecting the Sidelink resources from the resource pool to send the V2V data and the transmission parameter thereof may inevitably cause a resource conflict and interference between OBU terminals to reduce a transmission success rate of the V2V data. If multiple retransmissions are performed to increase the transmission success rate, a transmission delay may be increased. For achieving both a high success rate and a low delay, the number of vehicles simultaneously sending V2V signals within the same coverage must be limited, which makes it difficult to implement V2V communication of a large vehicle flow.
Therefore, for reducing interference between OBU terminals and improving V2V communication efficiency, it is necessary to increase a proportion of the In Coverage scenario and reduce a proportion of the Out of Coverage scenario as much as possible. Base station coverage and capacity of a telecommunication operator are planned according to a density distribution of terminals of a conventional type (for example, mobile phones), and it is difficult to ensure good coverage for the OBU terminals. More seriously, if the telecommunication operator is unwilling to perform base station upgrading and network optimization to support a V2V service in consideration of a cost problem, the OBU terminals may completely be located in the Out of Coverage scenario, and at this moment, the LTE V2V technology can only adopt random selection from a resource pool or “listen before talk” adopted by the IEEE 802.11p, and its performance is unlikely to be better than the IEEE 802.11p.